As materials having physiological oactive functions, there have been proposed a variety of materials, and there are given polyphenols as those having physiological functions, such as an antioxidative effect, an antihypertensive effect, and a hepatic function-improving effect. A chlorogenic acid, which is one of the polyphenols, has been reported to have a high antihypertensive effect, and is expected to find a wide range of applications in supplements and food and drink.
Investigations have hence been carried out to make developments in elevating purity and stability of the chlorogenic acid. For example, it has been reported that, when an extract of green coffee beans or an extract of roasted coffee beans is treated so as to have a specific concentration of solids and then brought into contact with acid clay and/or activated clay, formation of precipitates immediately after production and formation of secondary precipitates during long-term storage can be suppressed (Patent Document 1). In addition, an acidic drink containing a chlorogenic acid has been investigated. As result, there is a report that: a chlorogenic acid-containing composition has a problem that the composition becomes turbid specifically in an acidic range when the composition is diluted to a concentration appropriate as a drink, while the composition does not become turbid when the composition contains a high concentration of the chlorogenic acid; and the turbidity that occurs specifically in an acidic range when the composition is diluted to a concentration appropriate as a drink can be suppressed by bringing a dispersion or a solution obtained by dispersing or dissolving a chlorogenic acid-containing composition in a mixed solvent of an organic solvent and water into contact with a specific adsorbent, removing the resulting precipitates, controlling the concentration of the chlorogenic acid and pH to specific ranges to further form precipitates, and then subjecting to solid-liquid separation (Patent Document 2).
[Patent Document 1] JP-A-2008-266144
[Patent Document 2] JP-A-2012-31165